sub:assertion {
  sub:get-most-frequent-a-pred dct:description "This query returns the most frequent predicates used in assertions" ;
    dct:license <http://www.apache.org/licenses/LICENSE-2.0> ;
    a <https://w3id.org/kpxl/grlc/grlc-query> ;
    rdfs:label "Get most frequent assertion predicates" ;
    <https://w3id.org/kpxl/grlc/endpoint> <https://w3id.org/np/l/nanopub-query-1.1/repo/full> ;
    <https://w3id.org/kpxl/grlc/sparql> """prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>
prefix dct: <http://purl.org/dc/terms/>
prefix np: <http://www.nanopub.org/nschema#>
prefix npa: <http://purl.org/nanopub/admin/>
prefix npx: <http://purl.org/nanopub/x/>

select ?pred (count(distinct ?np) as ?predcount) where {
  graph npa:graph {
    ?np np:hasAssertion ?a .
  }
  graph npa:graph {
    ?np npa:hasValidSignatureForPublicKey ?pubkey .
    filter not exists { ?npx npx:invalidates ?np ; npa:hasValidSignatureForPublicKey ?pubkey . }
  }
  graph ?a {
    ?subj ?pred ?obj .
  }
} group by ?pred
order by desc(?predcount)
limit 50""" .
}